Lagrangian Flow Network approach to an open flow model

Concepts and tools from network theory, the so-called Lagrangian Flow Network framework, have been successfully used to obtain a coarse-grained description of transport by closed fluid flows. Here we explore the application of this methodology to open chaotic flows, and check it with numerical results for a model open flow, namely a jet with a localized wave perturbation. We find that network nodes with high values of out-degree and of finite-time entropy in the forward-in-time direction identify the location of the chaotic saddle and its stable manifold, whereas nodes with high in-degree and backwards finite-time entropy highlight the location of the saddle and its unstable manifold. The cyclic clustering coefficient, associated to the presence of periodic orbits, takes non-vanishing values at the location of the saddle itself.Comment: 7 pages, 3 figures. To appear in European Physical Journal Special Topics, Topical Issue on "Recent Advances in Nonlinear Dynamics and Complex Structures: Fundamentals and Applications

Computational studies of electronic and thermal properties of low dimensional materials

The control of low dimensional materials holds potential for revolutionizing the electronic, thermal, and thermoelectric materials engineering. Through strategic manipulation and optimization of these materials, unique properties can be uncover which enable more efficient and effective materials development. Towards the determination of nanoscale strategies to improve the electronic and phononic devices, computational simulations of modified low dimensional materials have been carried in this research. First, the electronic properties of chemically func tionalized phosphorene monolayers are evaluated with spin-polarized Density Functional Theory, as a potential method to tune their electronic properties. The functionalization not only leads to formation of additional states within the semiconducting gap, but also to the emergence of local magnetism. The magnetic ground state and electronic structure are investigated in dependence of molecular coverage, lattice direction of the molecular adsorption and molecule type functionalization. Furthermore, the physical and transport properties of phosphorene grain boundaries under uniaxial strain are evaluated by the use of Density Functional based Tight Binding method in combination with Landauer theory. In both grain boundary types, the electronic bandgap decreases under strain, however, the respective thermal conductance is only weakly affected, despite rather strong changes in the frequency-resolved phonon transmission. The combination of both effects results in an enhancement in the thermoelectric figure of merit in the phosphorene grain boundary systems. Finally, the thermoelectric properties of carbon nanotubes peapod heterostructures are studied and compared to pristine nanotubes using also the Density Functional based Tight Binding method and Landauer theory. It is found that the fullerene encapsulation modifies the electron and phonon transport properties, causing the formation of electronic channels and the suppression of vibrational modes that lead to an improvement of the thermoelectric figure of merit. The results of this thesis highlight the potential of strategic manipulation and optimization of low dimensional materials in improving their unique electronic and thermal properties, revealing promising avenues for improving electronic and phononic devices.:ABSTRACT i ZUSAMMENFASSUNG ii ACKNOWLEDGEMENT iv LIST OF FIGURES ix LIST OF TERMS AND ABBREVIATIONS xviii 1 Introduction 1 1.1 Motivation 1 1.2 Objectives and outline 6 2 Computational Methods 8 2.1 Density Functional Theory 8 2.1.1 The Many-Body System Hamiltonian and the Born-Oppenheimer approximation 9 2.1.2 Thomas-Fermi-Dirac approximation model 10 2.1.3 The Hohenberg-Kohn theorems 12 2.1.4 The Kohn-Sham orbitals equations 13 2.1.5 Exchange-correlation functionals 15 2.2 Density Functional Based Tight Binding method 16 2.2.1 Tight-binding formalism 17 2.2.2 From DFT to DFTB 20 2.2.3 Parametrization 22 2.3 Atomistic Green’s functions 23 2.3.1 Non-Equilibrium Green’s functions for modeling electronic transmission 23 2.3.2 Non-equilibrium Green’s function for modeling thermal transmission 27 3 Tuning the electronic and magnetic properties through chemical functionalization 3.1 Introduction 33 3.1.1 Black phosphorus as a 2D material 33 3.1.2 Chemical Functionalization of low dimensional systems 35 3.1.3 Bipolar Magnetic Semiconductors 36 3.2 Computational approach 38 3.3 Interface effects in phosphorene by OH functionalization 39 3.3.1 Single molecule functionalization 39 3.3.2 Lattice selection 43 3.3.3 Coverage 45 3.4 Chiral functionalization effect in phosphorene 48 3.5 Functionalizing phosphorene towards BMS 51 3.6 Summary 53 4 Tuning transport properties through strain and grain bound-aries 4.1 Introduction 54 4.1.1 Strain in low dimensional materials 54 4.1.2 Grain boundaries 56 4.2 Computational approach 58 4.2.1 Molecular systems 58 4.2.2 Electron and phonon transport and thermoelectric figure of merit 58 4.3 Structural modification by strain in GB systems 60 4.4 Electronic structure modification by strain in GB systems 63 4.5 Thermal transport modification by strain in GB systems 65 4.6 Thermoelectric figure of merit of strained GB systems 68 4.7 Summary 71 5 Tuning transport properties through hybrid nanomaterials: CNT peapods 73 5.1 Introduction 73 5.1.1 Carbon-based nanostructures 73 5.1.2 CNT peapods as hybrid nanomaterials 76 5.2. Computational details 77 5.2.1 CNT peapod model 77 5.2.2 Quantum transport methodology 78 5.3 Structural properties of CNT peapods 79 5.4 Electronic properties of CNT peapods 80 5.5 Thermal properties of CNT peapods 83 5.6 Thermoelectronic properties of CNT peapods 85 5.7 Summary 88 6 Conclusions and outlook 91 Appendices Appendix A Supplementary information to phosphorene functionalization A.1 Spin resolved density of states of 1-OH system 96 A.2 Spin valve model 97 Appendix B Supplementary information to phosphorene grain boundaries 98 B.1 Projected Phonon Density of States in GB1 98 B.2 Thermoelectric transport properties of GB2 99 Appendix C Supplementary information to CNT peapods 101 C.1 Geometry optimization of CNT peapods with larger CNT diameter 101 C.2 Additional analysis of electron transport properties 102 C.3 Phonon band structure of different CNT structures 104 C.4 Additional analysis of thermoelectric performance 105 REFERENCES 105 LIST OF PUBLICATIONS 131 PRESENTATIONS 132Die Kontrolle niedrigdimensionaler Materialien birgt das Potenzial für eine Revolutionierung der elektronischen, thermischen und thermoelektrischen Technologien. Durch strategische Manipulation und Optimierung dieser Materialien können einzigartige Eigenschaften aufgedeckt werden, die eine effizientere und effektivere Materialentwicklung ermöglichen. Um Strategien im Nanobereich zur Verbesserung elektronischer und phononischer Bauelemente zu ermitteln, wurden in dieser Forschungsarbeit rechnerische Simulationen modifizierter niedrigdimensionaler Materialien durchgeführt. Zunächst werden die elektronischen Eigenschaften von chemisch funktionalisierten Phosphoren-Monoschichten mit Hilfe der spinpolarisierten Dichtefunktionaltheorie als potenzielle Methode zur Abstimmung ihrer elektronischen Eigenschaften bewertet. Die Funktionalisierung führt nicht nur zur Bildung zusätzlicher Zustände innerhalb der halbleitenden Lücke, sondern auch zum Auftreten von lokalem Magnetismus. Der magnetische Grundzustand und die elektronische Struktur werden in Abhängigkeit von der molekularen Bedeckung, der Gitterrichtung der molekularen Adsorption und der Funktionalisierung des Moleküls untersucht. Darüber hinaus werden die Transporteigenschaften von Phosphoren-Korngrenzen unter uniaxialer Belastung mit Hilfe der auf Dichtefunktionen basierenden Tight-Binding-Methode in Kombination mit der Landauer-Theorie untersucht. In beiden Korngrenzentypen nimmt die elektronische Bandlücke unter Dehnung ab, die jeweilige Wärmeleitfähigkeit wird jedoch nur schwach beeinflusst, trotz ziemlich starker Änderungen in der frequenzaufgelösten Phononentransmission. Die Kombination bei der Effekte führt zu einer Erhöhung der thermoelektrischen Leistungszahl in den Phosphorkorngrenzensystemen. Schließlich werden die thermoelektrischen Eigenschaften von Kohlenstoffnanoröhren-Peapod-Heterostrukturen untersucht und mit denen von reinen Nanoröhren verglichen, wobei auch die auf Dichtefunktionen basierende Tight-Binding-Methode und die Landauer-Theorie verwendet werden. Es wird festgestellt, dass die Fullereneinkapselung die Elektronen- und Phononentransporteigenschaften modifiziert und die Bildung von elektronischen Kanälen und die Unterdrückung von Schwingungsmoden bewirkt, was zu einer Verbesserung der thermoelektrischen Leistungszahl führt. Die Ergebnisse dieser Arbeit verdeutlichen das Potenzial der strategischen Manipulation und Optimierung niedrigdimensionaler Materialien zur Verbesserung ihrer einzigartigen elektronischen und thermischen Eigenschaften und zeigen vielversprechende Wege zur Verbesserung elektronischer und phononischer Bauteile auf.:ABSTRACT i ZUSAMMENFASSUNG ii ACKNOWLEDGEMENT iv LIST OF FIGURES ix LIST OF TERMS AND ABBREVIATIONS xviii 1 Introduction 1 1.1 Motivation 1 1.2 Objectives and outline 6 2 Computational Methods 8 2.1 Density Functional Theory 8 2.1.1 The Many-Body System Hamiltonian and the Born-Oppenheimer approximation 9 2.1.2 Thomas-Fermi-Dirac approximation model 10 2.1.3 The Hohenberg-Kohn theorems 12 2.1.4 The Kohn-Sham orbitals equations 13 2.1.5 Exchange-correlation functionals 15 2.2 Density Functional Based Tight Binding method 16 2.2.1 Tight-binding formalism 17 2.2.2 From DFT to DFTB 20 2.2.3 Parametrization 22 2.3 Atomistic Green’s functions 23 2.3.1 Non-Equilibrium Green’s functions for modeling electronic transmission 23 2.3.2 Non-equilibrium Green’s function for modeling thermal transmission 27 3 Tuning the electronic and magnetic properties through chemical functionalization 3.1 Introduction 33 3.1.1 Black phosphorus as a 2D material 33 3.1.2 Chemical Functionalization of low dimensional systems 35 3.1.3 Bipolar Magnetic Semiconductors 36 3.2 Computational approach 38 3.3 Interface effects in phosphorene by OH functionalization 39 3.3.1 Single molecule functionalization 39 3.3.2 Lattice selection 43 3.3.3 Coverage 45 3.4 Chiral functionalization effect in phosphorene 48 3.5 Functionalizing phosphorene towards BMS 51 3.6 Summary 53 4 Tuning transport properties through strain and grain bound-aries 4.1 Introduction 54 4.1.1 Strain in low dimensional materials 54 4.1.2 Grain boundaries 56 4.2 Computational approach 58 4.2.1 Molecular systems 58 4.2.2 Electron and phonon transport and thermoelectric figure of merit 58 4.3 Structural modification by strain in GB systems 60 4.4 Electronic structure modification by strain in GB systems 63 4.5 Thermal transport modification by strain in GB systems 65 4.6 Thermoelectric figure of merit of strained GB systems 68 4.7 Summary 71 5 Tuning transport properties through hybrid nanomaterials: CNT peapods 73 5.1 Introduction 73 5.1.1 Carbon-based nanostructures 73 5.1.2 CNT peapods as hybrid nanomaterials 76 5.2. Computational details 77 5.2.1 CNT peapod model 77 5.2.2 Quantum transport methodology 78 5.3 Structural properties of CNT peapods 79 5.4 Electronic properties of CNT peapods 80 5.5 Thermal properties of CNT peapods 83 5.6 Thermoelectronic properties of CNT peapods 85 5.7 Summary 88 6 Conclusions and outlook 91 Appendices Appendix A Supplementary information to phosphorene functionalization A.1 Spin resolved density of states of 1-OH system 96 A.2 Spin valve model 97 Appendix B Supplementary information to phosphorene grain boundaries 98 B.1 Projected Phonon Density of States in GB1 98 B.2 Thermoelectric transport properties of GB2 99 Appendix C Supplementary information to CNT peapods 101 C.1 Geometry optimization of CNT peapods with larger CNT diameter 101 C.2 Additional analysis of electron transport properties 102 C.3 Phonon band structure of different CNT structures 104 C.4 Additional analysis of thermoelectric performance 105 REFERENCES 105 LIST OF PUBLICATIONS 131 PRESENTATIONS 13

Incidencia de la Gestión en el Área Financiera de Supermercado La Matagalpa en el Municipio de Matagalpa, en el I Semestre del año 2014

La incidencia de la Gestión en el Área Financiera de las Empresas de Matagalpa y Jinotega en el 2014 surge con el propósito de evaluar el manejo de dicha Gestión; estas actividades administrativas de seguimiento, control y monitoreo que realiza un administrador para lograr cumplir con las tareas propuestas que deben ser tomadas en cuenta para el adecuado manejo de una Empresa. El manejo de la Gestión en el Área Financiera de las empresas comerciales es de gran importanciaya que de esto dependerá el crecimiento o disminución de los valores financieros y del buen manejo de esto la empresa podrá proyectarse nuevos alcances que le permitan desarrollarse en el mercado. Se logró observar que en Supermercados La Matagalpa dentro de sus funciones el Gerente General realiza Gestiones en el Área Financiera, expresa que esta actividad es una de las bases esenciales para administrar sus finanzas y lograr sus objetivos, de esta forma, evaluar las diferentes alternativas que el mercado financiero les ofrece. En Supermercado La Matagalpa la Gestión Financiera se realizan de acuerdo a la situación que se va enfrentando en el momento que se presentan las necesidades financieras, cabe mencionar que aún cuando en el organigrama existe una Gerencia Financiera de la cual depende varios departamentos que están siendo dirigidos por el mismo Gerente General y se encarga de realizar las Gestiones de Financiamiento más apropiadas para la institució

Uncoupling fork speed and origin activity to identify the primary cause of replicative stress phenotypes

In growing cells, DNA replication precedes mitotic cell division to transmit genetic information to the next generation. The slowing or stalling of DNA replication forks at natural or exogenous obstacles causes "replicative stress" that promotes genomic instability and affects cellular fitness. Replicative stress phenotypes can be characterized at the single-molecule level with DNA combing or stretched DNA fibers, but interpreting the results obtained with these approaches is complicated by the fact that the speed of replication forks is connected to the frequency of origin activation. Primary alterations in fork speed trigger secondary responses in origins, and, conversely, primary alterations in the number of active origins induce compensatory changes in fork speed. Here, by employing interventions that temporally restrict either fork speed or origin firing while still allowing interrogation of the other variable, we report a set of experimental conditions to separate cause and effect in any manipulation that affects DNA replication dynamics. Using HeLa cells and chemical inhibition of origin activity (through a CDC7 kinase inhibitor) and of DNA synthesis (via the DNA polymerase inhibitor aphidicolin), we found that primary effects of replicative stress on velocity of replisomes (fork rate) can be readily distinguished from primary effects on origin firing. Identifying the primary cause of replicative stress in each case as demonstrated here may facilitate the design of methods to counteract replication stress in primary cells or to enhance it in cancer cells to increase their susceptibility to therapies that target DNA repair.The DNA Replication Group is part of the BFU2016-81796-REDC network of excellence. We thank all members of the group for discussions and Dr. Oscar Fernández-Capetillo and Dr. Ana Losada for useful comments on the manuscriptS

Low cost electromyogram and electrical muscle stimulator

Muscular system function could be ffected by neurological disorders such as cerebral strokes, injuries and neurological disorders. Healthcare experts usually relay on their experience to diagnose and recommend a specific treatment. However, there exist technological devices capable to measure the electrical activity in the muscle improving the diagnostic; also there exist devices capable to aid on the rehabilitation of the muscle known as Transcutaneous Electrical Nerve Stimulators. Nevertheless, these devices are only available on laboratories or well-equipped clinics due mainly to the relatively expensive cost. This manuscript presents a low-cost device capable not only to measure the electromyographic activity but also is capable to stimulate the muscles in order to improve the rehabilitation of the muscle. Data could be visualized on a generic computer using the sound card as a data acquisition. This paper presents the development of such devices and preliminary results

Evidencia de introgresión genética entre Pteronotus fulvus y Pteronotus gymnonotus (Chiroptera: Mormoopidae)

El subgénero Pteronotus comprende murciélagos insectívoros neotropicales de la familia Mormoopidae. Actualmente se consideran tres especies, P. davyi, P. fulvus y P. gymnonotus, con dos subespecies P. d. davyi y P. d. incae. En el presente trabajo se determinaron los linajes genéticos y las relaciones filogenéticas de P. d. davyi, P. fulvus, y P. gymnonotus, utilizando secuencias nucleotídicas del gen de Citocromo Oxidasa subunidad I (COI) del ADN mitocondrial, dos intrones (PRKCL y STAT5A) y el gen nuclear Activador de la Recombinación 2 (RAG2) del ADN nuclear. Posteriormente, se evalúo una posible introgresión genética entre P. fulvus y P. gymnonotus utilizando ADN nuclear (6 loci de microsatélites) y ADN mitocondrial (COI). Se observó una estructura genética mitocondrial bien definida, identificando tres linajes evolutivos que corresponde a los taxa descritos que se diversificaron entre 1.025 y 2.188 Ma, posiblemente en Centroamérica o al Norte de Sudamérica. Este periodo corresponde a oscilaciones climáticas y fluctuaciones del nivel del mar, que sucedieron en esta zona geográfica y que afectaron la composición y el hábitat de la región, características que pudieron haber promovido la diversificación del subgénero Pteronotus.En cuanto a la introgresión entre P. gymnonotus y P. fulvus, con los microsatélites se identificaron de 10 a 42 híbridos que corresponde al 5.7-35.2% del total de las muestras estudiadas, los resultados de las tasas de migración revelan que el flujo genético es histórico, con una mayor flujo genético de P. fulvus a P. gymnonotus. Mientras que los resultados con COI revelan una captura mitocondrial de P. fulvus en todos los individuos de P. gymnonotus de México, Guatemala y parte de Panamá, con un mayor número de migrantes de P. fulvus a P. gymnonotus (6.3 migrantes por generación P. fulvus a P. gymnonotus y 1.5 de P. gymnonotus a P. fulvus). Estos resultados indican la presencia de introgresión genética histórica y asimétrica, posiblemente facilitada por la colonización de P. gymnonotus en Centroamérica y México.The subgenus Pteronotus, neotropical insectivorous bats includes the Mormoopidae family, the which currently has three species P. davyi, P. fulvus and P. gymnonotus in where two subespecies are considered P. d. davyi y P. d. incae. In the present work, the evolutionary lineages and the phylogenetic relationships of P. d. davyi, P. fulvus and P. gymnonotus, were studied using nucleotide sequences of the Cytochrome Oxidase subunit I (COI) from the mitochondrial DNA, also two introns (PRKCL and STAT5A) and the Nuclear Gene Activator of the Recombination 2 (RAG2) of the nuclear DNA, subsequently a possible genetic introgression between P. fulvus and P. gymnonotus was evaluated using nuclear DNA (6 microsatellite loci) and mitochondrial DNA (COI). A well-defined mitochondrial genetic structure was observed, identifying three monophyletic evolutionary lineages, which correspond to the described taxa, which diversified between 1.025 and 2.188 Ma, possibly in Central America or the north of South America, this period of time corresponds to climatic oscillations in the geographical area and that may affected the composition and habitat of the region, characteristics that could have promoted the diversification of the subgenus Pteronotus. As for the introgression between P. gymnonotus and P. fulvus, we identified 10 to 42 hybrids corresponding to 5.7-35.2% of the total samples studied, while the results of the migration rates reveal that the introgression is historical and with a greater direction from P. fulvus to P. gymnonotus. The results with COI showed a mitochondrial capture of P. fulvus in all individuals of P. gymnonotus from Mexico, Guatemala and part of Panama (IMA, number of migrants by generation 6.3 from P. fulvus to P. gymnonotus and 1.545 from P. gymnonotus to P. fulvus). These results indicate the presence of historical and asymmetric genetic introgression, possibly facilitated by the colonization of P. gymnonotus in Central America and Mexico

Comparative Assessment of Pollutant Concentrations and Meteorological Parameters from TCEQ CAMS Sites at Houston and Rio Grande Valley Regions of Texas, USA in 2016

Spatial and temporal heterogeneity in pollutant concentrations exists at the intra-urban level. In this research work, the concentrations of various pollutants and meteorological parameters are characterized between various central ambient monitoring sites at Houston, TX, and the Rio Grande Valley Regions of South Texas. Meteorological (temperature, relative humidity, wind speed and direction) and pollutant (O3, SO2, CO, NO2, and various PM species) concentrations were downloaded from the appropriate Texas Commission on Environmental Quality (TCEQ) Central Ambient Monitoring Station (CAMS) sites for the year 2016. Correlation Analyses and Coefficient of Divergence (COD) analyses suggest that statistically significant differences occur between the various TCEQ CAMS sites in the Houston Region. Findings from this study will help the various stakeholders involved in assessing the overall air pollutants exposure burden for the local populations

Play therapy as a method of self-care for guidan renal transplant patient

Método educativo y terapéutico que convierte el tiempo libre en productivo, crea un ambiente confortable; la atención del paciente se centra en buscar alternativas de cuidado, lo que disminuye alteraciones emocionales provocadas por el ocio y el aislamiento durante la estancia hospitalaria.Hacer uso de la ludoterapia como herramienta de enfermería para brindar un cuidado integral, promover el bienestar físico y mental del paciente hospitalizado con trasplante renal. Metodología. Investigación acción en el que participaron 25 pacientes con insuficiencia renal. Se instrumentó un programa de orientación con cuatro sesiones, cada una consta de tres etapas: educativa, lúdica y evaluativa. Resultados. El análisis por núcleos temáticos arroja lo siguiente: cambio positivo en el estado de ánimo, disminuye la ansiedad y malestares físicos, facilita la comunicación y expresión de emociones, obtiene información para su autocuidado, permite detectar signos y síntomas de alarma de manera oportuna. Conclusión. Método educativo y terapéutico que convierte el tiempo libre en productivo, crea un ambiente confortable; la atención del paciente se centra en buscar alternativas de cuidado, lo que disminuye alteraciones emocionales provocadas por el ocio y el aislamiento durante la estancia hospitalaria

Efecto diurético del extracto acuoso de las hojas de Bixa orellana (achiote) en ratas.

La presente investigación tuvo como objetivo evaluar el diurético del extracto acuoso de las hojas de Bixa orellana (achiote) en ratas. El un estudio fue preclínico y se desarrolló en el laboratorio de Farmacología de la Escuela de Farmacia y Bioquímica, Facultad de Medicina Humana. Universidad San Pedro, Chimbote, Perú. Para lo cual se utilizó 36 ratas albinas Cepa Holtzman donde todos recibieron NaCl 0.9% 25 mL/kg, luego de 30 min los animales fueron separados en seis grupos de seis ratas cada una, y se procedió a la administración de los tratamiento siguientes: 1° grupo SSF 2mL/Kg, 2° furosemida 10 mg/kg °, el 3° hidroclorotiazida 200 mg/Kg y el 4°, 5° y 6° recibieron extracto en dosis de 50, 250 y 500 mg/kg respectivamente, El extracto acuoso evidenció la presencia de carbohidratos, azúcares reductores y taninos en abundante cantidad, aminoácidos libres, flavonoides, alcaloides y glicósidos en regular cantidad, heterósidos antraquinónicos y esteroides triterpénicos en poca cantidad; así mismo a una dosis de 500 mg/kg tiene mayor volumen promedio de orina (4,87 mL), demostrando ser dosis dependiente así mismo los valores promedios de furosemida fueron de 16,68 mL y el de hidroclorotiazida de 14,00 mL, encontrándose que a una dosis de 500 mg/Kg presenta el mayor porcentaje de excreción urinaria de 19,48% frente a furosemida de 66,72% e hidroclorotiazida al 56,00 %. Así mismo el extracto a dosis de 500 mg/Kg evidencia mayor porcentajes de actividad diurética con el estándar farmacológico furosemida 29,20%, y con el estándar hidroclorotiazida de 34,79%. Concluyendo que el extracto acuoso de las hojas de Bixa orellana (achiote) en ratas, posee efecto diurético.Tesi